Driving head for small lathes



Dec. 23, 1930. H. G. MILLER 1,786,022

DRIVING HEAD F011 SMALL LATHES Original Filed April 27, 1927 //f0//ryPatented Dec. 23, 1930 HARRY G. MILLER, OF DENVER, COLORADO DRIVING HEADFOR SMALL LATHES Application filed April 27, 1927, Serial No. 186,951.Renewed June 13, 1930.

This invention relates to improvements in driving heads for grindingmachines and pertains especially to driving heads designed to rotateinternal combustion engine valves about the axes of their stems during avalve grinding operation. The improvements herein disclosed areparticularly designed to be used in machines of the general typedescribed and claimed in my former application filed September 18, 1925,Serial No. 57,105. The valves to be ground difier in size and in thecontour of their upper surfaces, in

accordance with. differences in the internal.

combustion engines for which they are de- 1 slgned, and also inaccordance with the practice of the manufacturer. Some of these valveshave flat surfaces provided with pin receiving sockets on opposite sidesof their centers; othersare provided with diametrically extendingchannels; and others have dished or concave head surfaces provided withsockets or channels, which, in the different valves, are of differinglengths.

The object of this invention is to provide a driving head which will begenerally and, so far as is possible, universally adapted to engage inthe sockets or channels of valve heads of any kind in ordinary use forinternal combustion engine or motor driven ve- Q hicles, whereby suchvalves may be positively rotated about the axes of their stems incontact with a grinding wheel or other abrading surface. I Moreparticularly stated, the object of this invention is to provide adriving head adapted to be mounted .for rotation on a supporting headstock centering pin and which will be provided with axially yieldingprojections adapted to engage valve heads having widely spaced socketsto receive such projections; the chuck being equipped with aco-operating, yieldingly supported, floating member having valvee'ngaging projections which are located closer to the axis of rotation,and which may be in line with portions of the supporting pin and adapted to engage valve headsockets or channels beyond such portions of thepin,thus adapting the driving head for the engagement of valve headshaving extremely short channels or narrowly spaced sockets.

In the drawings Figure l is a plan view of a work holding carriage for agrinding machine, showing a valve as it 'is'supported thereby for' agrinding operation, a fragment of the grinding wheel being alsoillustrated.

Figure 2 is a detail sectional view of the driving head and valve, drawngenerally to a plane intersectingthe axis of rotation and showingfragments of the valve stem and supporting head stock, the dead centerpin being illustrated in full. Figure 3 is a detail view of the drivinghead. Figure 4 isa detail view of the floating work engaging disc. I

{Like parts are identified by the same referen'ce characters throughoutthe several views. The carriage comprises a supporting 'bar 10 providedwith a head stock lland tail stock 12. The head and tail stocks'areprovided with supporting pins 13 and 1 1 respectively, tail stock pin 14having a socket to I receive the end of the valve stem 16 and pressurebeingapplied in the direction of the headv stock by means of a manuallyoperated cam 17. A steady rest bracket 18 is secured to V the supportingrod or bar 10 and provided with a semi-cylindrical stem receiving rest19 engageable with the valve stemnear the valve disc 20. These parts areall shown and described in said former application and for the purposeof this application may be regarded asof ordinary construction, the samenot being claimed herein.

The driving head has a cylindrical body 22 adapted "to berotatively'supported on the pin 13. It preferably carries a pulley 23whereby 71 it may be driven by a belt 24, and it has work engaging pins25 socketed in body apertures 26 at diametrically opposite points. Thepins and their sockets are parallel with the axis of rotation. Theapertures 26 have internal shoulders against which the pin heads 27 mayseat when inserted from the rear or outer face of the body. Forward ofthese shoulders the apertures are reduced in diameter to substantiallythat of the pins, thereby providing guide bearings for the pins, thelatter being urged to a normal forward projection by coiled springs 28seated against the pin heads and held under compression by suitableplugs 29 threaded into the rear ends of the apertures. The projectingends of these pins are adapted to yieldingly engage in correspondinglyspaced valve head sockets, or channels of suitable length, whereby thevalves may be rotated under power derived through the pulley 23.

It will be observed that the diameter of the spindle 13 imposes aminimum limit to the spacing of the pins 25 whereby it becomesimpossible to socket such pins in the manner above described, much moreclosely to the axis of rotation than is indicated in Figure 2 of thedrawings. here the sockets in the valve heads are more closely spaced,or where the valve heads have channel-s too short to receive these pins25 it is necessary to provide auxiliary means for engaging such valveheads. For this purpose I provide a thin centrally apertured floatingdisc, or annulus, 30 which also has suitable apertures 31 adapted toloosely receive the pins 25. In a diametrical line at right angles to aline intersecting these apertures, I also provide-similar apertures 32in which the reduced ends of a set of supporting pins 33 may bereceived, these pins having heads 34 of suliicient size to preventdis-engagement of the annulus from the supporting pins 33. Pins 33 aremounted in the body 22 of the chuck in the same manner as abovedescribed with reference to the mounting of the pins 25, whereby the.supporting pins 33' and the annulus 30 may be pushed inwardly toward thebody 22 when the pins 25 are engaged in valve head sockets.

The annulus30 is providedwith a pair of projections 36 located in closeproximity to the centralaperture 37, which apertureis of less diameterthan the pin 13, but ofsuificient diameter to receive a pointed end; 380f the pin. These projections 36 may be adapted to engage closely.spaced socketaperturesin the valve head or short channels therein. And,by employing a concavo-convex annulus with the projections extendingfrom its convex surface it is obvious that the annulus may extend intoconcavely dished or recessed valve heads whereby relatively shortprojections 36 may be utilized, and power to rotate tlievalvetransmitted through the supporting pins 33 and the annulus 30. Owing tothe resilient mounting of the pins 33, the annulusmay be projected to,or if desired, even beyond, the ends of the pins 25 when the pro ections36 areutilized to rotate a valve head. It 1s not necessary that theannulus 30 should be projected beyond the ends of thepins 25 for thereasonthat when the projections 36 are in use,the pins 25 may be pressedbackwardly in their sockets by any portion of the valve head with whichthey may contact. Similarly as heretofore explained, the projections 36and the annulus 30 may be pressed backwardly when the pins 25 are inuse. In that case the pins 33 will be yieldingly moved into theirrespective sockets against the resistance of the springs therein.

Vi ith the above described construction it is possible to provide otherpins corresponding with the pins 25 or projections 36 supported as abovedescribed in positions oven hanging portions of the supporting pins andthereby meet the requirements for a chuck which will engage and rota toany valve head in commercial use.

A driving head constructed. as illustrated in the drawings will meet therequirements for any valve heads now in use for motor driven vehicles.It will be understood that the point of the dead center pin will bearagainst the central portion of the valve hcad in line with the axis ofthe stem, and that it will operate as a. centering pin for the valvehead. The point of the centering pin will co-operate with the operativeset of work engaging projections above described in steadying the headwhile the work engaging projections are rotating it. v

I claim:

1. A driving head of the described class comprising a body portion, aset of work engaging pins resiliently socketed in the body portion atequal distances from the central axis and an independently actingcarrier resiliently supported from the head and independently movablealong said pins, the carrier being provided with work engagingprojections at distances from the central axis different from those ofsaid pins whereby to engage work which is not engageable by said pinsfor work rotating purposes.

2. In a drivin head of the described class the combination with a bodyportion havi an axial aperture tor the reception of a supportingspindle, and also provided with pin receiving seckets parallel with saidaxis a d at equal t nces therefrom, work engaging pins resilientlymounted in said sockets and a carrier annulus resiliently supportedbeyond the end of the body from which said pins project, and providedwith work engaging projections in greater proximity to the axis thanthat of the said pins.

3. In a driving head of the described class the combination with a bodyportion having an axial aperture tor the reception of a snpportingcentering pin, and also provided with pin receiving sockets parallelwithsaid axis and at equal distances therefrom, work engaging pinsresiliently mounted in said sockets, and a carrier annulus resilientlysupported beyond the end of the body from which said pins project, andprovided with work engaging projections in greater proximity to the axisthan that of the said pins and in line with portions of said centralaperture.

4:. The combination with a body, of a driving head for rotating valveheads in grinding operations, of a set of resiliently mount- 7 ed workengaging pins projecting from one end of the body, another set oiresiliently mounted carrier supporting pins, a carrier annulus looselyconnected with the outer ends of the last mentioned pins and providedwith work engaging projections, operative with-- in the field ofoperation of the first mentioned pins, said carrier being apertured toallow said first mentioned pins to pass for engagement with the work,and said carrier being provided with a convex outer surface upon whichsaid work engaging projections are mounted.

6. A driving head for valve grinding machines comprising the combinationof a body portion and plural sets of interchangeably acting workengaging projections, each resiliently supported from the body portion,said body portion being centrally apertured and one set of saidprojections being in line with the aperture in the body at oppositesides of its central axis. I

7. In a driving head for rotating valve heads in a valve grindingmachine, the combination of a centering spindle provided with a taperedwork engaging point, a body ro tatably mounted on said spindle andprovided with driving connections, a set of work engaging pinsresiliently socketed in said body and projecting therefrom along linesparallel to the axis of the spindle, a set of carrier supporting pinssimilarly socketed in said body,

a carrier member spanning the space between said supporting pins andhaving an opening through which the spindle point PIOIIeCtS,

and a set of work engag ng projections mounted on the carrier in linewith portions of the spindle at opposite sides of its axis.

HARRY G. MILLER.

